Soldiers in war zones received phone calls of appreciation from President Barack Obama, while astronauts hovering above the Earth's surface feasted on turkey smuggled aboard the space shuttle Atlantis.
In New York City, Miss America Katie Stam waved to crowds from a Statue of Liberty float she shared with Meb Keflezighi, the first American in 27 years to win the New York City Marathon.
Shailesh Dighe and his family came to the fabled parade to snap pictures of celebrities including rapper Jay Sean and singer-actress Keke Palmer. Despite the crowds, Dighe said the parade is "totally worth it."
"When you watch it on TV, you don't get that feeling," said Dighe, who splits his time between Manhattan and Princeton, N.J.
For the first time, the parade route bypassed Broadway, which cuts a diagonal slice through Manhattan, as it made its way south from the Upper West Side to the finish at Macy's flagship store in Herald Square.
The new route traverses the grid of the city's streets and avenues, includes turns around five corners, and is slightly longer than in previous years - 2.65 miles compared with 2.5 miles.
Johanna Castillo, 38, of Guttenberg, N.J., said the new route seemed to better accommodate the crowds.
"I was very blessed to get here at the time I did and find a spot" a half-hour before parade time, said Castillo, who arrived with her two children.
Maryann Alonzo, 48, of Queens, N.Y., has been coming to the parade since she was a baby. She showed up Thursday with her daughter and friends to cheer on her father, who's been performing in the parade for 25 years as a clown.
"This is our Thanksgiving," Alonzo said. "More than the food."
Celebrity entertainment included Italian tenor Andrea Boccelli, comedian Jimmy Fallon, former "American Idol" star Katharine McPhee and singers Gloria Gaynor and Carly Simon.
Elsewhere, tens of thousands gathered in the streets of downtown Detroit for the 83rd annual America's Thanksgiving Parade. The country's longest-run Thanksgiving Day parade was held in Philadelphia for its 90th year.
In Detroit, where the September unemployment rate was 17.3 percent, parade organizers set up three locations where revelers could drop off donations of canned food for the area food bank.
Eugene Peterson, 35, an unemployed construction worker from Detroit, said he had plenty to be thankful for.
"I'm thankful we have a president who understands we're going through a hard time," Peterson said. "I'm thankful they extended unemployment (benefits) because there ain't no jobs around here. It's kind of like government showing yeah, they care."
Aboard Atlantis, astronauts expecting to give thanks with pantry leftovers were surprised by turkey dinners with candied yams, freeze-dried cornbread stuffing and green beans - just add water.
NASA suspected the station's new skipper was responsible for the Thanksgiving feast.
Obama enjoyed a quiet holiday at the White House with his family and telephoned 10 members of the U.S. military stationed in war zones to thank them for their service.
As daylight faded in Afghanistan, soldiers huddled inside a crude wooden hut to tuck into Thanksgiving turkeys the unit itself had fattened and to give thanks for having survived a year of combat.
Dense fog delayed some flights Thursday for Thanksgiving travelers headed to the Washington and Baltimore areas.
The Federal Aviation Administration says the fog prompted a ground stop for flights arriving Thursday morning at all three Washington-area airports. Departing flights were apparently not affected. The FAA lifted its ground stop by 10:30 a.m.